Censored Weibull statistics in the dielectric breakdown of thin oxide films

Abstract

Self-healing dielectric breakdown in thin oxide films has been shown to obey Weibull statistics after allowance has been made for both left and right censoring that is intrinsic to the measuring technique. Two overlapping distributions have been found under constant DC voltage stress testing but under ramp stress conditions these were not always observed. Nevertheless it is shown that the two types of test gave consistency in their analyses. Two particular features of the results reported are that the number of potential events, in some cases, was an exponential function of the applied field and that under ramp test conditions the magnitude of the applied potential at the breakdown estimator time appears to be constant and independent of the sample thickness. The implications of these observations are discussed.